JPH0383206A - Production of magnetic head - Google Patents

Abstract

PURPOSE:To improve the production efficiency in the production process of a magnetic head in which working to provide tracks is performed after forming the chip by disposing several head core blocks parallel to one another after the gap is formed, adhering these blocks to substrates so as to endure at the glass filling temp. and then subjecting them to working for tracks and glass filling. CONSTITUTION:Several numbers of rod-type head core blocks 21 for an all-track head are disposed parallel to one another in an angle corresponding to the azimuth angle. At the same time, both ends of each block 21 are made to adhere to the substrate 22 by such a method so as to endure against the glass filling temp. The adhesive used is an alumina-silica adhesive having the coefft. of thermal expansion alpha about 130 X 10<-7>/ deg.C, which gives almost no difference in elongation between the block 21 and the substrate 22. The direction A in the substrate 22 shown in the figure is parallel to the upper and lower end line 23 and is used for track working, finishing the sliding surface and slicing while one of the end lines 23 is used as the standard surface for the dicer process. The mounting direction B of the block 21 is the direction of R- polishing and the block 21 is disposed obliquely so as to make azimuth angle theta to the direction A.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a magnetic head used in information recording and reproducing devices such as video tape recorders (VTRs) and digital audio tape recorders (DATs).

[Conventional technology]

Magnetic tapes used in conventional consumer VTRs generally use iron oxide recording media, but 8mmV
Magnetic recording devices with high recording densities, such as TR and DAT, are being improved in quality by using metal-based recording media with high coercive force.

In order to fully exploit the characteristics of a magnetic tape, it is generally said that the saturation magnetic flux density (hereinafter referred to as B) of the head material needs to be five times or more the coercive force (hereinafter referred to as HC) of the tape. The Hc of iron oxide is approximately 600 (Oe), and that of metal tape is approximately 1400 (Oe).

On the other hand, the Bs of oxide magnetic material (ferrite), which is the magnetic head material used in consumer VTRs, is approximately 50.
Since it is 00G, it is more than 5 times and sufficient for iron oxide tape, but it is less than 5 times for metal tape, so 1400X5 is necessary to bring out its characteristics.
= 7000, and a BS of 7000G or more is required. Therefore, metal magnetic materials with high Bs (such as Sendust) have come to be used as magnetic head materials.

Conventionally, as a magnetic head using this type of sendust, a structure shown in FIGS. 7(a) and 7(b) is known. The magnetic head shown in the figure is called a "bulk type head", and before the head core halves 1a and lb are bonded together to form a gap, a track width regulating groove is formed, and then the track width is The regulating groove is filled with glass 2.

However, in order to manufacture this bulk type head, tracks are processed on the core halves 1a and lb before the gap is formed, so when welding the core halves 1aslb to each other, track alignment that requires high precision technology is required. Must.

Therefore, a magnetic head has been proposed that can omit the track alignment process that is necessary in the conventional bulk type head (see FIGS. 6(a) and 6(b)). This magnetic head is called an all-track head (hereinafter referred to as an AT head) because its entire width is a track, and as shown in FIGS. 6(a) and (b), this AT head consists of a pair of tracks. The half cores 10a and 10b are welded to each other, and a track width regulating groove 12 forming a track 11 is filled with glass 13, which is exposed on the tape sliding surface.

When manufacturing this AT head, first, a pair of rod-shaped head core block halves are welded together using silver solder or the like to form a gap, thereby forming a head core block. Next, a track machining (AT machining) step is performed to form a one-rack groove in this head core block, a glass filling process is performed to fill the track groove with glass, and an R-shape (arc-shaped) is formed on the tape sliding surface of the head core block after glass filling. R-polishing process to form curved surface shapes such as shapes, etc., sliding surface processing process to process the R-polished tape sliding surface, and after processing the sliding surface, head chips are sliced in a direction parallel to the track grooves. Processing is performed in the order of the slicing process to form.

[Problem to be solved by the invention]

In the manufacturing process of the magnetic head mentioned above, especially in the glass filling process, the head core block is exposed to high temperatures of nearly 700°C. There was a problem in that it was completely impossible to maintain the adhesion strength and adhesion accuracy of the blocks.

For this reason, conventionally, during track processing, multiple head core blocks were lined up on a single board and bonded with wax, then all the processed blocks were removed from the board and cleaned, and then in the glass filling process, the glass filling process was re-installed. It is attached to a jig and glass filling processing is performed. Furthermore, in each processing step after glass filling, it is necessary to attach each head core block to a jig dedicated to that step, position it, and remove it from the jig after processing. As a result of the above, the conventional process has become extremely inefficient.

The present invention has been made to solve such problems, and an object of the present invention is to provide a method for manufacturing a magnetic head that can greatly improve manufacturing efficiency by freeing up time for handling head core blocks in each process.

[Means to solve the problem]

A method for manufacturing a magnetic head according to the present invention includes arranging a plurality of head core blocks diagonally and in parallel at an angle corresponding to an azimuth angle, and arranging each head core block in a manner that
After adhering to the base so as to withstand the glass filling temperature, at least glass filling processing is performed while maintaining the positional relationship of each head core block.

In addition, a plurality of head core blocks are arranged diagonally in parallel at an angle corresponding to the azimuth angle, and each head core block is bonded to a base to withstand the glass filling temperature. A track processing step of forming track grooves on at least the surface of the head core block while maintaining the positional relationship of the core blocks, a glass filling processing step of filling the track grooves with glass, and a tape of the head core block after glass filling. R polishing step to form a curved surface shape on the sliding surface, sliding surface processing step to process the polished tape sliding surface, and slicing the head core block after sliding surface processing in the direction parallel to the track groove. The processing is performed in the order of the slicing process to form the head chip.

[Effect]

In the present invention, since the adhesive means that can withstand the glass filling temperature of 1 degree joins both ends of the head core block and the base, the head core block fixed to the base can be heated at high temperatures during glass filling processing. Even in this case, the bonded portions do not separate, and the positional relationship between the head core blocks when initially bonded can be maintained with high accuracy. Therefore, if multiple head core blocks are positioned relative to each other on the base first, a series of magnetic head processing steps after track processing can be performed in that state, increasing the manufacturing efficiency of the magnetic head. It can be significantly improved.

〔Example〕

The present invention provides a plurality of (
In this figure, six (6) rod-shaped head core blocks 21 are arranged parallel to each other at an angle corresponding to the azimuth angle, and both ends of each head core block 21 are attached with adhesive means that can withstand the glass filling temperature. It is assumed that a technique for bonding to the stand 22 (hereinafter referred to as multi-block bonding) is used. In the figure, A indicates the upper and lower edges 23 of the base 22.
, and indicates the direction of track machining (AT machining), sliding surface machining, and slicing machining. At this time, one of the edges 23 is used as a reference surface for dicer processing. The head core block 21 is arranged obliquely with respect to the direction A at an angle corresponding to the azimuth angle, and the mounting direction B of the block 21 is also the direction of R polishing.

The angle θ between the B direction and the direction orthogonal to the A direction is an azimuth angle. Note that a predetermined interval C is maintained between the head core blocks 21 that are adjacent to each other. It is preferable that this interval C be the minimum necessary dimension so that there is no bending of the cut line and no problem with the supply of cutting fluid during machining with a dicer. Can be minimized. However,
As shown in FIG. 1, by strictly determining the mutual positional relationship of each head core block 21 with respect to the base 22 in consideration of each processing step, automatic processing using a dicer becomes possible in each step.

Hereinafter, one embodiment of the present invention will be described based on FIGS. 2 to 4 (a) and (b). FIGS. 2(a) to 2(f) are plan views sequentially showing the manufacturing method of a magnetic head using multi-block adhesion in this embodiment. First, a gap is formed on a substrate 31 as a base. The latter six head core blocks 21 are arranged diagonally and parallel to each other at an angle corresponding to the azimuth angle (FIG. 6(a)), and then,
Both ends 33 and 34 of each head core block 21 are bonded to the substrate 31 using an inorganic adhesive 35 (FIG. 3(b)), thereby completing multi-block bonding.
This is sent to the next track processing step. In the track processing step, track processing is performed to form a plurality of track grooves on the surface of the head core block 21 according to the entry direction in FIG. 1 (FIG. 2(C)), and then glass filling is performed in the glass filling processing step. The track grooves are heated to a temperature of approximately 730° C. to fill the track grooves with glass (see (d) in the same figure), and then, at the same time, excess glass on the tape sliding surface of the head core block 21 after glass filling is removed. In order to form a curved surface shape, R polishing is performed in the B direction ((e) in the same figure), and then sliding surface processing is performed on the polished tape sliding surface in the A direction ((in the same figure) f)) Then, in a slicing step (not shown), the head core block 21 is sliced in the entry direction parallel to the track grooves, as shown in FIG. 6(a).
, a head chip as shown in (b) is formed.

FIG. 3 is a perspective view showing how the head core block 21 is processed in order, and the head chip 41 is formed through the following steps: track addition IC1 glass filling d, R polishing e1 sliding surface processing f1 slicing g. Manufactured.

As mentioned above, the reason why the adhesive fixing portions are provided at both ends of the head core block 21 is to lengthen the effective portion of the head core block 21 other than the adhesive portions, so that the block 21 can be used effectively. 31 and each head core block 2
This is to stabilize the machining conditions by regularly positioning 1 and 1.

Next, examples of adhesive structures will be described. The head core block 21 is made by welding together a pair of Sendust cores having lengths of, for example, 15 m and 17 m, and has a thermal expansion coefficient α of approximately 130×10 −7 /′C. At this time,
The substrate 31 (for example, thickness t = 5 + w) is also made of Sendust, and as an inorganic adhesive, the thermal expansion coefficient α is approximately 130 x 10.
If an alumina-silica material with a temperature of 1/200°C is used, the difference in elongation between the block 21 and the substrate will be almost zero even when heated to the glass filling temperature, and the load due to thermal stress on the bonded area can be kept low. This is the most preferred embodiment of the present invention.

The changes in the adhesive strength of the head core block before and after the glass filling process in this case are shown in Table 1, and there is almost no decrease in the adhesive strength due to heating to the glass filling temperature (730° C.).

Table 1 In addition, various processes from track processing to sliding surface processing were mainly performed using a dicing machine on multiple head core blocks with multi-block bonding, as shown in Figure 4 (a). In addition, sliding surfaces could be machined without any problem on all of the plurality of tracks formed on each head core block. In other words, the glass filling temperature (730℃
It can be seen that even after heating to ), the mutual positional relationship between the head core blocks when bonded for the first time is maintained.

If the positional relationship between the head core blocks is shifted due to heating, variations in sliding surface processing should occur between the head core blocks as shown in FIG. 4(b).

In the figure, G indicates the glass portion, G indicates the gap, G indicates the groove processed on the sliding surface, and r wl and w2 indicate the width dimension of the glass portion on the sliding surface, respectively. In addition, in FIG. 4(a), W 1=w
2 shows the case where the mutual positional relationship between the head core blocks during track machining is maintained even during sliding surface machining, and Fig. 4(b) shows that wI≠w2 and the head core blocks during track machining This shows a case where the mutual positional relationship between the blocks is not maintained during sliding surface machining.

In addition, the substrate material is 545C (for example, thickness t = 0.5au
Table 2 shows the changes in the adhesive strength of the head core block before and after the glass filling process in case a). Although the adhesive strength is slightly lower than in the previous case where Sendust was used as the substrate, Each process up to the moving surface process could be carried out without any problem as shown in FIG. 4(a).

Table 2 Therefore, according to the present invention, after positioning the head core blocks on the substrate before track processing, the series of slicing can be performed for multiple head core blocks by simply fixing them with adhesive means that can withstand the glass filling temperature. can be processed, and the process can be greatly simplified. Of course, even after slicing, if the head chip is fixed with wax, for example, the substrate after slicing can be used as a holder for supplying chips during chip attachment.

Regarding the R polishing process, the depth may be increased by using a grinder or by flat polishing, and the R shape may be created by tape wrapping after slicing, or the R shape may be created by tape wrapping only after slicing. Further, a wire saw may be used for the slicing process.

Regarding the relationship between the materials of the head core block, inorganic adhesive, and substrate, as in the adhesive structure example, as long as the adhesive strength and adhesion accuracy are within a range where there is no practical problem after glass filling, the adhesive structure example Not limited to cases. The same applies to the length of the head core block and the thickness of the substrate.

The shape of the base may be a rod-like one as shown in FIG. 5(a), or a separate type where the bonded portions at both ends of the head core block are independent, as shown in No. 511U(b). Further, the adhesive portion of the head core block 21 may be other than both ends.

Further, the head core block may be bonded by other bonding means such as welding, as long as the bonding strength and bonding accuracy are maintained even at the glass filling temperature. The glass filling temperature is determined by the filled glass and is not limited to the examples.

〔Effect of the invention〕

As explained above, in the present invention, each head core block is bonded to the base so that it can withstand the glass filling temperature, so even if the base and head core block are heated during the glass filling process, the bonded portion will not break. Moreover, the positional relationship between the head core blocks at the time of initial bonding can be maintained with high accuracy. Therefore, if the mutual positions of a plurality of head core blocks on the base are determined first, slicing can be performed in that state, and the efficiency of manufacturing the magnetic head can be greatly improved.

[Brief explanation of drawings]

FIG. 1 is a plan view showing the arrangement of head core blocks in the present invention, and FIGS. 2 to 4 (a) and (b) are views showing one embodiment of the present invention. ~(f) are plan views showing the order of manufacturing steps, FIG. 3 is a perspective view showing the state in which the head core block is processed, and FIG. 4(a)
, (b) is a plan view showing the state after the sliding surface has been processed on the head core block, FIGS. 5(a) and (b) are plan views showing other embodiments of the present invention, and FIG. (a) and (b) are
FIGS. 7(a) and 7(b) are a plan view and a front view of an AT head manufactured according to the present invention, respectively, and FIGS. 7(a) and 7(b) are a plan view and a front view, respectively, of a conventional bulk type head. 21...Head core block, 22...Base, 31...Base (substrate), 41...Head chip.

Claims (1)

[Claims] 1. In a method for manufacturing a magnetic head in which track processing is performed after gap formation, a plurality of head core blocks after gap formation are arranged in parallel to each other, and each head core block is capable of withstanding glass filling temperature. A method of manufacturing a magnetic head, comprising performing at least track processing and glass filling processing on the head core block while the head core block is adhered to a base. 2. In a magnetic head manufacturing method in which track processing is performed after gap formation, a plurality of head core blocks after gap formation are arranged parallel to each other, and each head core block is bonded to a base to withstand the glass filling temperature. In this state, the head core block is subjected to track processing to form at least track width regulating grooves, glass filling processing to fill the track width regulating grooves with glass, and sliding surface processing to determine the width of the tape sliding surface of the head. A method for manufacturing a magnetic head, characterized in that a slicing process is performed in the above order to form a head chip by slicing a head core block in a direction parallel to a track width regulating groove.